Concealed adjustment mechanism for folding chairs



Feb. 21, 1961 M. 1. THOMAS 2,972,373

CONCEALED ADJUSTMENT MECHANISM FOR FOLDING CHAIRS Filed July 27, 1959 2 Sheets-Sheet 1 is?? m ffg INVENTOR'.J

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Feb. 2l, 1961 M. l. THOMAS 2,972,373

CONCEALED ADJUSTMENT MECHANISM FOR FOLDING CHAIRS Filed July 27, 1959 2 Sheets-Sheet 2 INVENTOR.

. 7a/PTOM ffm/*M5 BY Mrmwfy nited States Patent CONCEALED ADJUSTMENT MECHANISM FOR FOLDING CHAIRS Morton I. Thomas, R.D. 2, Box 182H, Monroe, N.Y.

Filed July 27, 1959, Ser. No. 829,617

2 Claims. (Cl. 155-139) The invention here disclosed relates to folding chairs and other like furniture of the tubular frame form of construction.

Special objects of the invention are to provide mechanism for holding the Achair in various positions of adjustment which will be entirely concealed and protected and which will be rigid and strong enough to carry all loads and withstand any rough treatment to which such furniture might ordinarily be subjected.

This invention is related to that disclosed in oopending patent application Serial No. 766,351, led October 9, 1958, Patent No. 2,920,686 of January l2, 1960, in which the chair frame is held in diiferent positions of adjustment by upstanding lugs on the legs of the chair projecting through slots in the undersides of tubular arms into engagement with stop shoulders concealed within the arms but is distinguished from that invention in the arrangement and construction of the upstanding lugs and stop shoulders.

Specifically in the present invention the stop shoulders vwhich are located within the tubular arms are carried by tubular pieces which closely fit within the tubular arms so as to brace and reinforce the same and which carry the slots for guiding and stopping the lugs, instead of the slots in the tubular arms and the lugs being constructed with abrupt shoulders which will act as stops against the stop shoulders provided on the insert tubular pieces.

`Other distinctions and advantages are set forth and will appear in the course of the following specification.

The drawings accompanying and forming part of the specication illustrate a present commercial embodiment of the invention but as will become apparent, structure may be modified and changed as regards the immediate illustration, all within the true intent and scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawings is a broken side elevation of a folding chair having the invention incorporatedv therein, broken lines indicating various positions of adjustment.

Fig. 2 is an enlarged broken sectional detail showing companion elements of the adjustment mechanism engaged in the upright position of the chair shown in full lines in Fig. l.

Fig. 3 is a broken longitudinal sectional View of the inserted stop member secured in position in the chair arm, looking downward on these parts.

Fig. 4 is a bottom plan view of the tubular stop member.

Fig. 5 is a broken part sectional View similar to Fig. 3 showing the arm rest raised to release the holding and positioning mechanism.

Fig. 6 is an enlarged and broken cross sectional view on substantiallythe plane of the line 6-6 of Fig. 2.

Fig. 7 is a cross sectional detail as on substantially the plane of line 7-7 of Fig. 5.

Fig. 8 is a top plan view of one of the chair arms with the back frame appearing in section as on substantially the plane of line 8 8 of Fig. l.

The chair illustrated as an example of folding furniare ICC

ture to which the invention may be applied is shown as comprising front and back leg frames 10, 11 of U formation connected at their upper ends by pivot studs or rivets 12', a seat frame 13 pivoted to the front leg frame at 14,

a back frame 15r pivoted at its lower end at 16 to the seat frame and arm rests 17 pivoted to theback frame at 18 and adjustably-connected to the leg frames by the new stop mechanism constituting the presentv invention.

This mechanism comprisesV in each instance a short length of tubing 19 sized to closely tit within the tubular arm 17, as shown particularly in Figs. 5 and 6, so as to partially support and reinforce the tubular arm practically throughout its circumference and provided with a longitudinal slot 20 in line with and generally of the same dimensions as the slot 21 in the arm, this tube having cross bars 22, 23, 24 impressed inthe top thereof for engagement by the upstanding lug 25, Figs. 2 and 5, carried by the chair legs.

The inserted tubular bracket 19 is shown in Fig. 4 as made from la single` piece of sheet metal, usually steel, rolled into substantially cylindrical shape with the end edges separated suiciently to form the guidingl slot 20 and with lugs 26 extended from one end of the rolled piece into edge to edge engagement at 27 with the correspondingly narrowed portion 28 on the opposite end of the sheet.

This provides a, rigid, light but strong construction'r reinforcing the chair arm and enabling the chair frame to stand' rough treatment without injury. j

Particularly important isv that the inserted tube provides a smooth edge guide slot 20 for the stop lug 25l as distinguished from a rough edge guide slot in the softer metal, usually aluminum, of the chair arm.

Also, as shown in Figs. 2 and 5 the guide slot` in the steel insertV provides fixed abutmentI ends 29, 30 positively limiting movement'of the stopv lug 25, apart from the slot ends 31, 32 in the aluminum tubing saving such tubing from bending and tearing.

Fitting closely as it does in the tubular arm the inserted tubular piece may be securely held by a single cross rivet as shown at 33.

The stop lugs 25 on the chair legs are shown as simple plates curved at their lower ends as shown at 34 to fit closely about the upper ends of the rear chair legs 11, held in that relation by the pivot lugs 12 and the extra rivets 3S extending through the rear leg frame.

As shown in Fig. 6, these stop lugs project straight up through the aligned slots 21 and 26 in the arm and bracket and have angularly turned upper ends 36 to prevent accidental disengagement of the arms from these lugs.

The upstanding portions of the stop lugs which project up into the tubular stop members are shown as having sharply angled shoulders 37, Figs. 2 and 5, to cooperate With the shoulders 29 at the ends of the slots 20 in the inserted stop brackets.

The arms are shown as of hairpin form made up each of a length of tubing bent upon itself providing parallel portions 38, 39, Fig. 8, connected by a bend 40. The tubular stop bracket 19 is shown located' and secured in the outer one, 39, of these parallel lengths and the inner length 38 is shown pivotally secured to the back frame 15 by a U clip 41 held thereto by a rivet 42, the sides of the clip embracing the inner length 38 and the pivot stud 18 extending through these sides of the clip and through both lengths of the chair arm.

The tubular stop brackets inserted and rigidly held within the tubular arms form guides for the upstanding lugs on the chair legs and assure smooth easy action in the folding, unfolding and angular adjustments of the chair frame. This construction. takes all wear olf the aluminum tubing and prevents breaking, tearing or indenting of the softer metal. Also the inserts of harder metal correct any possible misalignment when the parts are assembled.

The adjusting mechanism in this invention is fully concealed and practically entirely covered, protecting occupants or users of the chair against any possible injury.

The tubular inserts, made up in the rolled sheet metal form disclosed, are relatively light and inexpensive. Because of this formation they are to an extent diametrically expansive and compressible and thus automatically adjustable to the cross sectional dimensions of the tubular chair arms. While substantially cylindrical, the sides of these units may be flattened somewhat asiindicated at 43, ll-Tigsu` and 6, to facilitate the formation of the cross pieces 22,23, 24 providing the stop shoulders and forming depressed bridges across the attened sides. All parts are of simple durable construction and by reason of their special construction must be assembled in the way in which they are intended to cooperate and hence cannot be put together in the wrong relation.

" What is claimed is: t

l. A folding chair with concealed adjustment means comprising in combination, front and back leg frames pivotally connected together at their upper ends, a seat frame pivoted at its forward end to the front leg frame, a back rest frame pivotally connected at its lower end to said back leg frame and to said seat frame, tubular arm rests pivotally connected at their rearward ends to said back rest frame and having longitudinal slots in the lower sides of the same, upstanding lug plates on the upper ends of said leg frames projecting upward through said slots rand tubular inserts ixedly secured within said tubular arm rests, said tubular inserts being of sheet metal rolled into substantially cylindrical shape to tit within the tubular arm rests with opposing ends of the same in spaced relation forming slots in line with the slots in the arm rests and with lugs projecting across the ends of said slots in position to be engaged by said upstanding lug plates on the .leg frames, the upper portions of said tubular inserts being depressed into transversely extending spaced cross bars "2,972,37a-f ,A g e" Y for engagement by said llug plates and the sides pt saig tubular inserts being flattened inwardly in line with said transversely extending cross bars.

2. A folding chair with concealed adjustment means comprising in combination, front and back leg frames pivotally connected together at their upper ends, a seat frame pivoted at its forward end to the front leg frame, a back rest frame pivotally connected at its lowerendjto said back leg frame and to said seat frame, tubular'arm rests pivotally connected at their rearward ends to said baek rest frame and having longitudinalslots in the lower sides of the same, short lengths of tubingin close fitting engagement within the slotted portions of said tubular arm rests, said lengths vof tubing beingof harder and more rigid material than the arm rests to brace and reinforce portions of the arm rests weakened by said slots therein, said lengths of tubing having open slots in alignment with the slots in the arm rests` and the slots in the lengthsof tubing being closed at opposite ends, upstanding lug plates on the upper ends of said leg frames projecting upward through the slots in the tubular arm rests and the slots in the length of tubing enclosed within the arm rests and the closed ends of the slots in the tubing forming stops limiting the extent of movement of the lug plates within the arm rests, means securing said lengths of tubing in fixed position within the tubular arm rests lined up with the slots therein in register with the slots in the tubular arm rests, the upper portions of said inserted lengths of tubing being depressed downwardly into transversely extending relatively spaced cross bars engageable by the upstanding lug plates to hold the connected frame parts in various positions of adjustment.

References Qited in the file of this patent UNITED STATES PATENTS 396,427 Record Dec. s, 1905 2,801,683 Lambert Aug. 6, 1957 2,920,686 Thomas Jan. l2, 1960 

